Files
systemd/src/basic/memory-util.c
Jan Janssen 3f92dc2fd4 boot: Simplify object erasure
This erase_obj() machinery looks like voodoo and creates an awful lot of
noise as soon as we get back to building with -O0. We can do this in a
more simple way by introducing a struct that holds the information we
need on cleanup. When building with optimization enabled, all this gets
inlined and the eraser vanishes.
2023-01-09 18:58:54 +01:00

41 lines
1.1 KiB
C

/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include <unistd.h>
#include "memory-util.h"
size_t page_size(void) {
static thread_local size_t pgsz = 0;
long r;
if (_likely_(pgsz > 0))
return pgsz;
r = sysconf(_SC_PAGESIZE);
assert(r > 0);
pgsz = (size_t) r;
return pgsz;
}
bool memeqbyte(uint8_t byte, const void *data, size_t length) {
/* Does the buffer consist entirely of the same specific byte value?
* Copied from https://github.com/systemd/casync/, copied in turn from
* https://github.com/rustyrussell/ccan/blob/master/ccan/mem/mem.c#L92,
* which is licensed CC-0.
*/
const uint8_t *p = data;
/* Check first 16 bytes manually */
for (size_t i = 0; i < 16; i++, length--) {
if (length == 0)
return true;
if (p[i] != byte)
return false;
}
/* Now we know first 16 bytes match, memcmp() with self. */
return memcmp(data, p + 16, length) == 0;
}